This invention relates to a method of making a label-equipped sheet and product and, more particularly, to a sheet or form wherein the label is die cut from base stock constituting the sheet and held in place by a pressure sensitive adhesive-equipped release liner until needed for use.
It has become increasingly desirable to provide sheets generally and business forms particularly of minimal thickness for ease in processing through computer printers, especially table top personal computers with associated printers. One approach to achieve this has been to die cut the form itself to provide a removable label. This art is well known for die cut labels generally in U.S. Pat. Nos. 3,914,483 and 4,246,058 and for business forms in U.S. Pat. No. 4,379,573.
However, with the processing of sheets such as business forms through printers and the subsequent converting of the connected forms into a roll or a zig-zag pack, it has become increasingly difficult to provide a label having sufficient "tack" while avoiding oozing of adhesive during processing of the form through the printer--particularly laser printers which generate substantial heat. Even where adhesive has been omitted--as by having the release liner overlap the adhesive (see U.S. Pat. No. 5,011,559), the seepage or oozing persists, particularly when significant amounts of strong adhesives like hot melts, are employed.
According to the invention, the foregoing problem is solved by providing a pattern of coatings on the web patch constituting the release liner. More particularly, a web ply is first coated with a pattern of release material such as a silicone in a pattern so as to leave an uncoated perimeter, i.e., a generally rectangular frame for a rectangular patch.
Thereafter, the entire ply is overcoated substantially over its already coated face with pressure sensitive adhesive--especially on most of the uncoated perimeter. When performed continuously, we omit the release coating from both longitudinal and transverse bands and thereafter coat with adhesive these areas as well as the previously release coated areas. When the patches are severed from a continuous ply and applied to a form or other label carrier constructed of label stock, the perimetric frame of the release liner patch adheres strongly to the form, effectively preventing oozing during laser printer printing. This strong adhesion effectively freezes the release liner patch in place on the form. This "frozen" area constitutes a dam effectively preventing the migration from the adhesive from the central part of the patch, i.e., the part equipped with the release liner. This "freezing" and damming stem from the fact that there is no release material in the perimetric frame area so that the two plies (patch and label stock) can bond together. This bonding serves as an effective barrier to seepage of adhesive.
In adding, in effect, adhesive to the border of the release liner ply patch we achieve, in addition to preventing oozing or creep of the adhesive, the significant advantage of securing the release liner ply to the form. Should an ordinary release liner ply, i.e., one without the adhesive border of our invention, become detached, the now-uncovered adhesive on the rear face of the label stock form could adhere the form unintentionally and most undesirably to an adjacent form.
The details of the inventive method and construction can be seen in the ensuing specification.